1. Field of the Invention
The present invention relates to a motion reduction apparatus for reducing motions caused by incoming waves impacting on a structural body floating on water such as floating bridges, warehouses, parking lots, platform work ships, oil drilling platforms and a floating body having the motion reduction apparatus.
2. Description of the Related Art
When installing a floating bridge or floating parking lot, or working on a stationary platform ship, waves hitting such a floating bridge, parking lot or platform ship can sometimes cause the structural bodies to oscillate, so that it is necessary to reduce the severity of motion that such floating bodies may encounter.
Various apparatuses for reducing motion of a floating body have been proposed. For example, the present inventors have already proposed a method in a Japanese Patent Applications, First Publication, No. 2000-142569 and Japanese Patent Application, No. 2000-12790 (not published). The apparatus proposed in the Japanese Patent Application, First Publication, No. 2000-142569 has a plumb plate extending through the water surface on the wavefront side on the floating main body to reduce motion of the floating body. Also, in a wave-resistant large-scale floating body described in the Japanese Patent Application, No. 2000-12790, L- or inverted L-shaped break-wave structures of different shapes are provided on the wavefront side of the large-scale floating body to reduce motion of the floating body.
However, although such motion reduction apparatuses described above are able to reduce motion to some extent by adopting the prescribed structures, it is insufficient for many purposes. Therefore, there has been a demand for a motion reduction apparatus to further improve the safety of operation by reducing motion even more reliably.
The present invention is provided to resolve the problem described above, and an object is to provide a motion reduction apparatus that reliably reduces motion of a floating object to improve the safety of operation.
To achieve the object of the present invention, in a first aspect of the invention, a motion reduction apparatus for a floating body floating on water comprises a plumb plate provided at least on a wavefront side of a floating main body and separated from the floating main body by a specific distance and extended beyond a bottom surface of the floating main body substantially in a vertical direction.
According to the motion reduction apparatus, incoming waves impact the floating main body and the plumb plate and some of the incoming waves also flood through the flow sections, so that the wave energy that can act on the floating main body is reduced and the plumb plate reduces rolling or pitching of the floating main body, thus reliably reducing motion of the floating body to provide improved safety of operation of the floating body.
In a second aspect of the invention, the plumb plate is supported at a specific location of the floating main body by means of a plurality of stay members arranged on the floating main body in parallel so as to provide flow sections between the stay members for flooding with incoming water.
According to the motion reduction apparatus, the plumb plate can be supported at a desired location using a simple structure.
In a third aspect of the invention, the floating main body is orthorhombic-shaped, and the plumb plate is provided at least on one side section along the longitudinal direction of the floating main body.
According to the motion reduction apparatus, plumb plate can reliably suppress rolling motion of the floating main body.
In a fourth aspect of the invention, the plumb plate is constructed so as to be retractable above a bottom surface of the floating main body.
According to the motion reduction apparatus, when the floating main body is adopted to a platform work ship, for example, interference with cruising operation of the ship can be avoided by raising the plumb plate above the floating main body when not in use.
In a fifth aspect of the invention, the motion reduction apparatus for a floating body floating on water comprises a horizontal plate provided at least on a wavefront side of a floating main body and separated from the floating main body by a specific distance and extended substantially along a horizontal direction.
According to the motion reduction apparatus, incoming waves impact the side section of the floating main body while some of the incoming waves flood through the flow sections, so that the wave energy that can act on the floating main body is reduced and the resistance offered by the horizontal plate and the flow sections can suppress rolling or pitching motion of the floating main body, thus reliably reducing motion of the floating body to improve the safety of operation of the floating body.
In a sixth aspect of the motion reduction apparatus, an upper surface of the horizontal plate is situated at substantially at the same height as the bottom surface of the floating main body.
According to the motion reduction apparatus, resistance offered by the horizontal plate reliably reduces rolling.
In a seventh aspect of the invention, the horizontal plate is supported at a specific location of the floating main body by means of a plurality of stay members arranged on the floating main body in parallel so as to provide flow sections between the stay members for flooding with incoming water.
According to the motion reduction apparatus, the horizontal plate can be supported at a specific location using a simple structure.
In an eighth aspect of the invention, the floating main body is orthorhombic-shaped, and the horizontal plate is provided at least on one left side section or a right side section along the longitudinal direction of the floating main body.
According to the motion reduction apparatus, rolling motion of the floating main body can be reliably suppressed using the horizontal plate.
In a ninth aspect of the invention, the horizontal plate is constructed so as to be retractable above a bottom surface of the floating main body.
According to the motion reduction apparatus, when the floating main body is adopted to a platform work ship, for example, interference with cruising operation of the ship can be avoided by raising the horizontal plate above the floating main body when not in use.
In a tenth aspect of the invention, the motion reduction apparatus for a floating body floating on water comprises a swing plate provided at least on a wavefront side of a floating main body and separated from the floating main body by a specific distance so as to enable to position the swing plate in a retracted position situated above a bottom surface of the floating main body, or in a horizontal position situated substantially at the same height as the bottom surface of the floating main body; or in a vertical position to extend downward beyond the bottom surface of the floating main body.
According to the motion reduction apparatus, when there are no interfering objects nearby, the swing plate can be moved to the horizontal position to reliably reduce motion of the floating main body, while when there are interfering objects nearby, the swing plate can be positioned vertically to reliably reduce motion of the floating main body. Further, when not in use, the swing plate can be raised to the retracted position so as to prevent interference.
In an eleventh aspect of the invention, the motion reduction apparatus for a floating body comprises a water surface plate provided at least on either a front section or a back section of a floating main body having an orthorhombic shape in disposed along a water surface.
According to the motion reduction apparatus, when the incoming waves impact on the front section or the back section of the floating main body, the horizontal plate and the flow sections offer resistance to suppress rolling motion to enable to reliably reduce motion of the floating main body.
In a twelfth aspect of the invention, the motion reduction apparatus for a floating body comprises a plate member provided at least on a wavefront side of a floating main body disposed in such a way that an edge section of the plate member proximal to the floating main body is separated from the floating main body by a specific distance.
According to the motion reduction apparatus, the incoming waves impact on the floating main body and the plate member while some of the incoming waves flood through the flow sections, so that the wave energy acting on the floating main body can be reduced, and the plate member can suppress rolling or pitching motion so as to reliably reduce motion of the floating body to improve the safety of operation of the floating body.
In a thirteenth aspect of the invention, the plate member is disposed so as to be inclined at an angle with respect to a bottom surface of the floating main body.
According to the motion reduction apparatus, incoming waves impact on the floating main body and the plate member while some of the incoming waves flood through the flow sections to reduce the wave energy acting on the floating main body and the plate member enables to suppress rolling or pitching motion so that motion of the floating body can be reliably reduced to improve the safety of operation of the floating body. Further, the angle of the plate member can be changed to maximize the reduction of rolling or pitching motion according to the cresting period of the incoming waves.
In a fourteenth aspect of the invention, the plate member is supported at a specific location of the floating main body by means of a plurality of stay members arranged in parallel on the floating main body so as to provide flow sections between the stay members for flooding with incoming water.
According to the motion reduction apparatus, the plate member can be supported at a specific position using a simple structure.
In a fifteenth aspect of the invention, the floating main body is orthorhombic-shaped, and the plate member is provided along the longitudinal direction at least on either a left side section or a right side section of the floating main body.
According to the motion reduction apparatus, the plate member can reliably suppress rolling motion of the floating main body.
In a sixteenth aspect of the invention, the plate member is constructed so as to be retractable above a bottom surface of the floating main body.
According to the motion reduction apparatus, when the floating main body is adopted to a platform work ship, for example, interference with cruising operation of the ship can be avoided by raising the horizontal plate above the floating main body when not in use.
In a seventeenth aspect of the invention, the plate member is supported vertically by hinging means.
According to the motion reduction apparatus, incoming waves impact on the floating main body and the plate member while some of the incoming waves flood through the flow sections to reduce the wave energy acting on the floating main body and the plate member absorbs wave energy to enable to suppress rolling or pitching motion so that motion of the floating body can be reliably reduced to improve the safety of operation of the floating body.
In an eighteenth aspect of the invention, the plate member is supported on the hinging means arranged on the floating main body in parallel, and flow sections are provided in the hinging means for flooding with incoming water.
According to the motion reduction apparatus, the plate member can be supported using a simple structure.
In a nineteenth aspect of the invention, the motion reduction apparatus for a floating body floating on water comprises an L-shaped plate member provided at least on a front section or a back section of a floating main body and disposed in such a way that the horizontal portion of the L-shaped plate member faces outward, and that the bottom surface of the L-shaped plate member is situated below the water level.
According to the motion reduction apparatus, when the incoming waves impact on the front or back section of the floating main body, the plate member and the flow sections offer resistance to suppress pitching motion so as to reliably reduce motion of the floating body to provide safety of operation of the floating body.
In a twentieth aspect of the invention, the motion reduction apparatus for a floating body floating on water having a floating main body of an orthorhombic shape comprises a water surface plate along a water surface or an outwardly extending L-shaped plate member, disposed on either a front section or a back section of the floating main body, to extend in a longitudinal direction in such a way that a bottom section of the L-shaped plate member is situated below the water surface.
According to the motion reduction apparatus, when the incoming waves impact on the front or back section of the floating main body, the plate member and the flow sections offer resistance to suppress pitching motion so as to reliably reduce motion of the floating body to provide safety of operation of the floating body.
In a twenty-first aspect of the invention, the plumb plate is subdivided by gaps formed substantially at right angles to a direction extending from the plumb plate.
According to the motion reduction apparatus, similar to the case of providing a solid plumb plate, incoming waves impact on the floating main body and the plumb plate while some of the incoming waves flood through the flow sections so that the wave energy acting on the floating main body can be reduced and the plumb plate suppresses rolling or pitching motion so as to reliably reduce motion of the floating body and to improve the safety of operation of the floating body.
In a twenty-second aspect of the invention, the horizontal plate is subdivided by gaps formed substantially at right angles to a direction extending from the horizontal plate.
According to the motion reduction apparatus, similar to the case of providing a solid horizontal plate, incoming waves impact on the floating main body and the horizontal plate while some of the incoming waves flood through the flow sections so that the wave energy acting on the floating main body can be reduced and the horizontal plate suppresses rolling or pitching motion so as to reliably reduce motion of the floating body and to improve the safety of operation of the floating body.
In a twenty-third aspect of the invention, the plate member is subdivided by gaps formed substantially at right angles to a direction extending from the plate member.
According to the motion reduction apparatus, similar to the case of providing a solid plate member, incoming waves impact on the floating main body and the plate member while some of the incoming waves flood through the flow sections so that the wave energy acting on the floating main body can be reduced and the plate member suppresses rolling or pitching motion so as to reliably reduce motion of the floating body and improving the safety of operation of the floating body.
According to twenty-fourth aspect of the invention, a motion reduction apparatus for a column-shaped floating body has a motion reduction plate disposed on an outer periphery of the floating main body approximately at the same height as a bottom section of the floating main body.
According to the motion reduction apparatus, incoming waves impact not only on the floating main body and the motion reduction plate but the characteristic pitching and rolling periods are also shifted to a longer period so that the wave energy acting on the floating main body can be reduced so as to reliably reduce motion of the floating body to improve the safety of operation of the floating body.
In a twenty-fifth aspect of the invention, the floating main body is hollow, and a motion reduction plate is provided on the outer as well as on the inner periphery of the floating main body at approximately the same height as the bottom section of the floating main body.
According to the motion reduction apparatus, incoming waves impact on the floating main body and the motion reduction plate and the characteristic pitching and rolling periods are shifted to a longer period so that the wave energy acting on the floating main body can be reduced even more than the in the floating body recited in aspect twenty-four so as to reliably reduce motion of the floating body to improve the safety of operation of the floating body.
A floating body relating to the present invention has a floating main body and a motion reduction apparatus according to any one of the motion reduction apparatuses disclosed in aspects 1 to 25.
According to the floating body, high safety of operation of the floating body can be realized because of the reduction in motion achieved by the motion reduction plates.